Saturday, December 8, 2012

December 17-19 Potential Winter Storm

There is potential (key word potential) for a winter storm from the perspective of a weather model. Let's take a closer look.

This is the Hour 216 (9 day) forecast from the European ECMWF model. Displayed above are values of sea level pressure (SLP)- lower values (cool colors) show storm systems, higher values (warmer colors) show quieter and warmer weather. The forecast above calls for a strong storm system to be present in the Plains, with a minimum central pressure of 990 millibars. That is pretty strong, and if enough cold air is available in Canada, a snow event could be possible in the north Plains.

The last forecast image from the ECMWF is hour 240, or 10 days away, We now see our storm system has further strengthened into a low pressure system with a minimum central pressure of 989 millibars. There is more to this than just a three-digit number. Notice the extension of light green colors to the northwest and southeast. The reason why this is significant is because it means that the system is being stretched, possibly into two systems. One system would likely go northeast into southern Canada, and the second system would probably head east and up the coast. But that's only IF it separated into 2 systems, and this is 10 DAYS OUT.

Adding even more uncertainty to the mix is the lack of support from the American GFS model. Usually, the GFS and ECMWF are on the same page, but if one model does not support the other, confidence is drastically reduced.

Andrew

11 comments:

Anonymous said...

Hey Andrew!


I was hearing somthing about a possible noreaster in the 21-26 timeframe in the midatlanitc and the northeast. Any possibility of that happening? If so, it would be awesome if you could make a post about it


Thanks!

Andrew said...

I will look into it! Thanks for mentioning it!

Anonymous said...

So do you think the Chicago area will ever get any snow? We have yet to see any and have broken an all-time 280 day record without any snow, and it's depressing! MAKE IT SNOW!!!!

Andrew said...

Snow will fall in Chicago this winter.

Anonymous said...

But do you think Chicago will see more than last years' 18"?

Andrew said...

More than likely.

Anonymous said...

I don't know about Chicago proper, but I hear northwest Indiana is supposed to get a pretty good lake-effect snow event tomorrow night, especially Porter county. What's your thoughts on that possibility?

Aran Jacobs said...

I have been looking at that too anonymous because I live in Porter County.

Anonymous said...

Wow! What a small world!

Anonymous said...

Andrew i your in your comment that the GFS is not supporting the storm of 17 -19 especially the last frame, but that last one run look just like the 18z run on the storm frame of the 14 -16 possible storm, is it possible the GFS is only seeing one storm for that whole time period from the 14- 18

Anonymous said...

Andrew the reason i asked if the GFS is reading only one storm that whole period, on 18z run for the storm of the 14-16 and the last run of the storm of the 17 - 19 that the other model is showing. the low pressure is the same 988 - 989. is it likely that 2 separate storms that close to gather would have that strong of low pressure.